<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script src="jquery-3.6.0.js"></script>
		<style>
			div {
				width: 60px;
				height: 60px;
			}
		</style>
	</head>
	<body>
		<button id="btn1">点击淡入div元素</button>
		<button id="btn2">点击淡出div元素</button>
		<button id="btn3">点我让颜色变浅</button><br>
		<div id="con">
			<div style="background-color: #0000FF;"></div>
			<div style="background-color: #ADFF2F;"></div>
			<div style="background-color: aqua"></div>
		</div>
		<script>
			$("#btn1").click(function(){
			  $("#con").fadeIn();
			});
			$("#btn2").click(function(){
			  $("#con").fadeOut();
			});
			$("#btn3").click(function(){
			  $("#con").fadeTo(1000,0.4);
			});
		</script>
	</body>
</html>
